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71.
Escherichia coli JM83 [F- ara delta(lac-proAB) rpsL [phi 80d delta (lacZ)M15]] in midlog growth phase at 30 degrees C were exposed to 60 Hz sinusoidal magnetic field of 3 mT of nonuniform diverging flux, inducing a nonuniform electric field with a maximum intensity of 32 microV/cm using an inductor coil. Exposed and unexposed control cells were maintained at 30.8 +/- 0.1 degrees C and 30.5 +/- 0.1 degrees C, respectively. Quadruplicate samples of exposed and unexposed E. coli cells were simultaneously radiolabeled with 35S-L-methionine at 10 min intervals over 2 hr. Radiochemical incorporation into proteins was analyzed via liquid scintillation counting and by denaturing 12.5% polyacrylamide gel electrophoresis. The results showed that E. coli exposed to a 60 Hz magnetic field of 3 mT exhibited no qualitative or quantitative changes in protein synthesis compared to unexposed cells. Thus small prokaryotic cells (less than 2 microns x 0.5 micron) under constant-temperature conditions do not alter their protein synthesis following exposure to 60 Hz magnetic fields at levels at 3 mT. 相似文献
72.
Photo-DSC was used, to study, in situ, the photo-ageing of polycyclo-octene which is a semi-crystalline elastomer. The ‘crystallizability’, which is the ability of the polymer to crystallize, was tightly dependent on the exposure time and was used to follow the photo-ageing.The irradiation system of photo-DSC was also compared with a usual accelerating device and no difference was detected in the chemical alteration of the polymeric matrix. Meanwhile, with photo-DSC, the photo-ageing was accelerated compared to a usual accelerating device. By using photo-DSC, atmosphere, exposure time, light intensity and ageing temperature were accurately controlled. 相似文献
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74.
Abstract: The aim of this paper is to present a novel un‐notched fatigue test specimen in which a biaxial stress state is achieved using a uniaxial loading condition. This allows the problem of multi‐axial fatigue to be studied using relatively common one‐axis servo‐hydraulic testing machines. In addition the specimen presented here is very compact and can be made using a small volume of material (100 × 40 × 4.5 mm). For this specimen, the degree of biaxiality, defined by the parameter is equal to approximately 0.45. The specimen geometry was optimised using the Dang Van multi‐axial fatigue criterion. In addition to use as a fatigue specimen, it has been demonstrated that the biaxial specimen presented here is also suitable for biaxial tensile tests, to determine the rupture strength of a material in a biaxial stress state. Two different materials have been investigated: The first was wrought aluminium 2024‐O in the form of 5 mm sheets. The second was a cast aluminium‐silicon alloy AlSi7Cu0.5Mg0.3, commonly used in automotive and aeronautical applications. The fatigue strengths were determined at 2 × 106 cycles and at various R‐ratios using a staircase procedure. For the aluminium 2024, it is shown that the biaxial stress state increases the maximum permissible first principal stress when compared to the uniaxial condition. However, in terms of the cast aluminium alloy, it has been demonstrated that this type of fatigue specimen is not suitable for materials containing casting defects, in particular micro‐shrinkage pores, because the volume of material, in which the stress state is biaxial, is not large enough. 相似文献
75.
Myriam Paire Laurent Lombez Jean-François GuillemolesDaniel Lincot 《Thin solid films》2011,519(21):7493-7496
A spatially resolved electroluminescence (EL) imaging experiment is developed to measure the local sheet resistance of the window layer, directly on the completed CIGS cell. Our method can be applied to the EL imaging studies that are made in fundamental studies as well as in process inspection. The EL experiment consists in using solar cell as a light emitting device: a voltage is applied to the cell and its luminescence is detected. We develop an analytical and quantitative model to simulate the behavior of CIGS solar cells based on the spread sheet resistance effect in the window layer. We determine the repartition of the electric potential on the ZnO, for given cell's characteristics such as sheet resistance and contact geometries. Knowing the repartition of the potential, the EL intensity is measured and fitted against the model. The procedure allows the determination of the window layer sheet resistance. 相似文献
76.
Hyun Jung Hwang Nayeon Kim Allison B. Herman Myriam Gorospe Jae-Seon Lee 《International journal of molecular sciences》2022,23(17)
Aging causes a progressive decline in the structure and function of organs. With advancing age, an accumulation of senescent endothelial cells (ECs) contributes to the risk of developing vascular dysfunction and cardiovascular diseases, including hypertension, diabetes, atherosclerosis, and neurodegeneration. Senescent ECs undergo phenotypic changes that alter the pattern of expressed proteins, as well as their morphologies and functions, and have been linked to vascular impairments, such as aortic stiffness, enhanced inflammation, and dysregulated vascular tone. Numerous molecules and pathways, including sirtuins, Klotho, RAAS, IGFBP, NRF2, and mTOR, have been implicated in promoting EC senescence. This review summarizes the molecular players and signaling pathways driving EC senescence and identifies targets with possible therapeutic value in age-related vascular diseases. 相似文献
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78.
Vineet Nagrath Olivier Morel Aamir Saeed Malik M. Naufal B. M. Saad Fabrice Meriaudeau 《Peer-to-Peer Networking and Applications》2016,9(2):328-343
Cloud computing is a methodology and not a technology. Adaptation of cloud computing services for robotic applications is relatively straightforward while adaptation of underlying ideas will require a new design attitude. Cloud computing is a cost-effective and dynamic business model. Currently cloud robotics is understood as a client server methodology which enables robots utilize resources and services placed at centralized servers. These cloud servers treat robots as any other client computer offering them platform, infrastructure, process or algorithm as a service. HTM5 is an OMG MDA based multi-view meta-model for agent oriented development of cloud robotic systems. HTM5 encourages design of peer-to-peer service ecosystems based on an open registry and matchmaking mechanism. In peer-to-peer cloud robotics, a robot can trade its hardware, software and functional resources as a service to other robots in the ecosystem. The peer-to-peer trade in such systems may be driven by contracts and relationships between its member agents. This article discusses trade-view model of HTM5 methodology and its use in developing a cloud robotic ecosystem that implements peer-to-peer, contract based economy. The article also presents a case study with experiments that implement distributed artificial intelligence and peer-to-peer service oriented trade on simulated and real robot colonies. 相似文献
79.
A pattern is a model or a template used to summarize and describe the behavior (or the trend) of data having generally some recurrent events. Patterns have received a considerable attention in recent years and were widely studied in the data mining field. Various pattern mining approaches have been proposed and used for different applications such as network monitoring, moving object tracking, financial or medical data analysis, scientific data processing, etc. In these different contexts, discovered patterns were useful to detect anomalies, to predict data behavior (or trend) or, more generally, to simplify data processing or to improve system performance. However, to the best of our knowledge, patterns have never been used in the context of Web archiving. Web archiving is the process of continuously collecting and preserving portions of the World Wide Web for future generations. In this paper, we show how patterns of page changes can be useful tools to efficiently archive Websites. We first define our pattern model that describes the importance of page changes. Then, we present the strategy used to (i) extract the temporal evolution of page changes, (ii) discover patterns, to (iii) exploit them to improve Web archives. The archive of French public TV channels France Télévisions is chosen as a case study to validate our approach. Our experimental evaluation based on real Web pages shows the utility of patterns to improve archive quality and to optimize indexing or storing. 相似文献
80.
SPETA: Social pervasive e-Tourism advisor 总被引:1,自引:0,他引:1
Angel García-Crespo Javier Chamizo Ismael Rivera Myriam Mencke Ricardo Colomo-Palacios Juan Miguel Gómez-Berbís 《Telematics and Informatics》2009
Tourism is one of the major sources of income for many countries. Therefore, providing efficient, real-time service for tourists is a crucial competitive asset which needs to be enhanced using major technological advances. The current research has the objective of integrating technological innovation into an information system, in order to build a better user experience for the tourist. The principal strength of the approach is the fusion of context-aware pervasive systems, GIS systems, social networks and semantics. This paper presents the SPETA system, which uses knowledge of the user’s current location, preferences, as well as a history of past locations, in order to provide the type of recommender services that tourists expect from a real tour guide. 相似文献